Means for forming extensible and retractable cords



Feb. 19, 1952 c, JUDISCH 2,586,763

MEANS FOR FORMING EXTENSIBLE AND RETRACTABLE CORDS Fil'ed Sept. 18, 1948 2 SHEETSSHEET 1 Feb. 19, 1952 c, JUDISCH 2,586,763

MEANS FOR FORMING EXTENSIBLE AND RETRACTABLE CORDS 2 SHEETS-SHEET 2 Filed Sept. 18, 1948 5 U1 w u 0 15 LL n Patented Feb. 19, 1952 MEANS FOR FORMING EXTENSIBLE AND RETRACTABLE CORDS Carl H. J udisch, Hamden, Conn., assignor to The Whitney Blake Company, Hamden, Conn., a corporation of Connecticut Application September 18, 1948, Serial No. 49,954

Claims.

The present invention relates to improvements in means for forming cords and relates more particularly to improvements in means for forming extensible and retractable cords, i. e., cordsof substantially helical form which may be extended and which by their inherent tension will retract themselves into substantially their original form when extending forces are released.

Cords of the type referred to are mainly formed of rubber or other elastic or resilient material and, as is well known in the art, are employed for a variety of different purposes. For instance, some such cords have one or more electrical conductors incorporated within them in order to serve as yielding connections for electric toasters, electric irons, telephone instruments, etc. Other such extensible and retractable cords may omit the one or more electric conductors referred to and be utilized to serve as substitutes fo key chains for personal wear. 7

It has been common practice in the art of producing extensible and retractable cords to wind such cords upon rods or arbors and aftersecuring the ends in place, subject to the partiallyformed cord to the action of heat to thereby vulcanize the cord if the same is formed of rubber, or to set the cord in the event that th same is formed of non-vulcanizable but elastic material such, for instance, as any one or more of a wide variety of the synthetic resins. The means employed in the prior art for retainin the ends of the cord to the arbor or rod have notbnly been time consuming to use, but have also occasioned harmful mutilation to the end-portions of the coils by applying thereto deforming pressures.

One of the main objects of the present invention is to provide superior means whereby extensible and retractable cords may be vulcanized or set in a simple, convenient and economical manner and without unduly deforming the terminal-portions of such cords.

A further object of the present invention is to provide superior means of the character just above referred to, and further adapted to serve in connection with the production of extensible and retractable cords having the pitch of their convolutions extending in either rightor lefthand directions.

Other objects and advantages will appear to those skilled in the art from the following when considered in conjunction with the accompany- Fig. 1 is a perspective view showing a preferred embodiment of the present invention which includes a mandrel and two complemental terminalholding heads with one terminal-end of the cord anchored in one of said heads and the cord partly wound on the mandrel and with the complemental terminal-holding head in its retired position;

Fig. 2 is a perspective view of one of the two similar terminal-heads detached;

Fig. 3 is a top or plan view thereof;

Fig. 4 is a sectional view taken on the line 4-4 of Fig. 3;

Fig. 5 is a View similar to Fig. 1 but showing the complete winding of the coil upon the mandrel and opposite terminal-ends of the cord respectively held in position by the complemental terminal-holding heads preparatory to heating the assembly to set or vulcanize the cord;

Fig. 6 is a View in side elevation of the cord after its removal from the device and after having been subjected to a heat treatment;

Fig. 7 is an end view thereof; and

Fig. 8 is a transverse sectional view of the cord taken on the line 8 -8 of Fig. 6.

For the purpose of making clear a preferred form of the present invention, there is illustrated in the accompanying drawings a device or means for forming extensible and retractable helical cords, which means comprises a rod-like mandrel ID and two complemental and correspondin terminal-holding heads respectively generally designated by the reference characters It and I2 and which are adapted to be mounted upon the said mandrel.

The mandrel It may be formed of a suitable metal and substantially corresponds in diameter to the desired internal diameter of the helical cord to be formed thereon. The terminal-holding heads II and 12 may be conveniently formed of cast metal such, for instance, as die-cast aluminum.

Inasmuch as each of the terminal-holding heads II and I2 corresponds to the other, similar reference characters will be applied to both to designate corresponding features.

Each terminal-holding head includes a flangeportion 13 and an integral hub-portion [4 pro-- jecting outwardly away from. the said flangeportion. Extending substantially axially through both the flange-portion I3 and the hub-portion it above described, is a bore l5 sized to havea sliding fit upon the mandrel If]. v

In its face remote from its integral hub-portion l 4, each flange-portion I3 is formed with a recess 16 which is substantially concentric with the left-hand pitch.

accompanying drawings, the terminal-end of the bore l5 and of a depth in an axial direction sub stantially corresponding to the diameter of the material from which the helical cords are to be formed. Leading substantially tangentially out of the recess [6 are two terminal-holding passages Ila and I'll) which, at their outer ends, intersect the periphery of the flange-portion 13. The depths of the said terminal-holding passages Ila and Ill) are substantially the same as the depth of the recess l6 proper.

The hub-portion I4 of each'terminal-holding head II and I2 is formed on its outer periphery with an integral longitudinal rib l8. Extending radially from the bore [5 outwardly through the hub-portion I4 and its rib I8, is a threaded passage I9 which is adapted to receive any suitable fastening-screw such, for instance, as the headless setscrew 28 shown in the head I i in. Figs. 1 and 5. or the thumbscrew 2l-:-shown in the terminalholding head l2 in the same figures.

The particular cord 22 illustrated in the accompanying drawings includes. three electrical conductors 23, 24 and 25, each of which is provided with an individual sheath of insulation 26 jointly enclosed within ajacket 2'! formed of a vulcanizable rubber compound (either synthetic, natural .or mixtures thereof) or a resilient elastic thermoplastic synthetic resin such, for instance, as polyvinylchloride. The jacket v21 may be applied in any suitable manner, though ordinarily this is done by extruding the same over the desired number of conductors or by extruding without conductors where desired.

. Utilization Normally,'the terminal-holding head H, which "is here used as a winding-head as hereinafter described, will be held in a fixed position adjacent one end of the mandrel I0, by means of a suitable fastening-screw such, for instance, as the head less setscrew shown in Figs. 1 and 5. The complemental terminal-holding head [2, which is here used as a clamping-head as also described hereinafter, is intended to be readily shifted in an axial direction on the mandrel l0 and for that purpose isprovided with the conveniently-matered into either the terminal-holding passage Ila 'or the similar passage l'lb, depending upon whether the finished extensible and retractable cord is to be initially formed with a rightor In the instance shown in the cord 22 is shown extending tangentially outwardly through the terminal-holding passage Ila. The mandrel 10, together with its rigid terminal-holding head Il, may be slightly rotated in the direction indicated in Fig. l to cause the convolu- *tion or partial convolution immediately adjacent th'e'said terminal-end to fit within the recess [6.

The direction of rotation indicated in Fig, 1 will result in imparting to the cord, in its final form, a pitch which extends ina right-hand direction.

After the location of the terminal-end of the cord as just above referred to, the mandrel 10 .may be rotated (preferably by an electric motor or the like) until the desired amount of cord has been wound upon the mandrel, whereupon the rota'tlon'of the said mandrel may be stopped and the mandrel l0, terminal-holding heads II and I2 and the now-helically-wound cord 22, may be placed in an oven or otherwise subjected to appropriate elevated temperatures to vulcanize and set the jacket El in the event that it is formed of vulcanizable material, or to merely set the said jacket in the event it is formed of nonvulcanizable material, to thereby relieve strains on the said jacket and cause it to retain its helical form after being released from restraint.

After the cord 22 has been properly set and cooled, the thumbscrew 2! may be released and the terminal-holding head l2 removed in an axial direction from the adjacent end of the mandrel l0, following which the now-formed cord may be also removed in the same manner, whereupon it will assume substantially the condition illustrated in Fig. 6. By reference to Fig. 6, it will be noticed that the convolutions of the cord 22 have slightly opened up or separated from each other, which is the usual result with most compounds employed for forming the jacket 2 1.

The now-set cord may have its convolutionsreversed to secure a greater degree of retractable tension, in any one of the manners well known in the art such, for instance, as by rewinding the said cord upon another mandrel to change its pitch from the right-hand pitch shown to alefthand pitch. This reversal will cause the convolutions of the cord to snugly abut against each other when relieved of extending forces and to resist the extending forces to a greater degree than would be the case were the said'cord not to be reversed.

By means of the terminal-heads H and l2,the cord and its terminals may be effectively held in desired positions while being heated, without causing appreciable distortion or mutilation of the jacket 21 or its equivalent. Furthermore, by means of the said terminal-heads, the operations of winding the cord upon the mandrel and removing it therefrom are greatly speeded up and facilitated to thereby reduce costs of production.

The invention may be carried out in other specific ways than those herein set forth withoutdeparting from the spirit and essential characteristics of the invention, and the present embodiments are, therefore, to be considered in all respects as illustrative and not restrictive,.and all changes coming within the meaning and equivalency range ofthe appended claims areintended to be embraced therein.

I claim:

1. A windingrform for resiliently extensible coiled cords, comprising a winding-arbor; a winding-head on arbor; a clamping-headremovable from and longitudinally adjustable on said arbor, saidheads having confronting .faces each provided with first an endless cord-fitting groove, of which the inner side wall is formed by said arbor, and a branch groove leading substantially tangentially from said first groove to the periphery of the head, said first groove and branch groove in said winding-head being of sufficient depth to receive and retain the leading end'of a cord to be wound on said arbor and adaptedto form it into the greater portion of the first-wound.

turn and the adjacent terminal end of the wound cord, and the other head being adapted to be clamped against the opposite end of the wound cord with the last turn and the adjacent terminal end of the same received and retained in said first groove and coordinated branch groove, respectively, of said clamping-head.

2. A winding-form as set forth in claim 1, in which said clamping-head is also angularly adjustable on said arbor for aligning said branch groove in the former with the adjacent terminal end of a wound coil on said arbor.

3. A winding-form as set forth in claim 1, in which said first and branch grooves in each of said heads are of a depth substantially equal to the diameter of the cord.

4. A winding-form as set forth in claim 1, in which said arbor extends outwardly beyond said winding-head so that the ends of said arbor may be journaled for cord-Winding purposes.

5. A winding-form for resiliently expansible f'coiled cords, comprising a Winding-arbor; a wind- --ing-head .on said arbor; a clamping-head removably mountable on said arbor, said heads having'confronting faces each provided with first an endless cord-fitting groove, of which the inner side wall is formed by said arbor, and a branch groove leading substantially tangentially from said first groove to the periphery of the head, said first groove and branch groove in said Winding-head being of sufiicient depth to receive and retain the leading end of a cord to be wound on said arbor and adapted to form it into the greater portion of the first-wound turn and the adjacent terminal end of the wound cord, and the other head being adapted to be mounted on said arbor in clamping engagement with the opposite end of the wound cord with the last turn and the adjacent terminal end of the same being received and retained in said first groove and coordinated branch groove, respectively, of said clamping head.

CARL H. JUDISCI-I.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 458,115 Thomson Aug. 18, 1891 629,115 Turney "July 18, 1899 2,272,228 Thornburg et a1. Feb. 10, 1942 2,452,434 Crehan et al. Oct. 26, 1948 

